Sound recording, sonagraphic analysis and playback experiments to investigate the information conveyed by different versions of certain vocalizations of Laughing Gulls. Playback experiments to test whether parent Laughing Gulls can recognize their chicks individually by ear. Experimental investigation of the effects of auditory stimulation on the pre-hatching behaviour of Laughing Gull Chicks and the effects of experience of such stimulation on post-hatching responsiveness of the chicks. "Message-meaning" analysis of social interactions of adult Laughing Gulls during the breeding cycle, with special attention to nest-relief ceremonies. Demographic study of breeding of Laughing Gulls in the Brigantine National Wildlife Refuge, and investigations of the occurrence and function of egg-shell carrying by Laughing Gulls. Observational and experimental study of the breeding behaviour of Clapper Rails. Descriptive and experimental study of the development of social behaviour in Laughing Gulls.